The present invention relates to tools for setting fasteners having pin members with pull grooves and more particularly to tools having a plurality of jaws for gripping the pull grooves.
In setting multi-pieced fasteners, including a pin and sleeve or collar, of types such as those shown in the U.S. Pat. Nos. 2,527,307 and 2,531,048 issued to L. C. Huck on Oct. 24, 1950 and Nov. 21, 1950, respectively, it has been the practice to utilize a tool having a plurality of independently movable chuck jaws. The latter are generally shown in the above noted patents to L. C. Huck and the details of the same are exemplified in the U.S. Pat. No. 3,107,806 issued Oct. 22, 1963 to G. J. Van Hecke et al. The chuck jaws have teeth adapted to grip pull grooves on the pin.
With such jaw structures it is possible under certain conditions, such as pin insertion, for the jaws to move out of axial alignment with each other. When such misalignment occurs and the tool is actuated, the pull grooves on the pin are gripped by less than the full complement of jaws; this can lead to stripping of the jaw teeth, stripping of the pull grooves and/or ultimate failure of one or more jaws.
In addition such jaw structures are normally held closed in a radially inward position by a spring biased jaw follower assembly. Thus, in order to insert the pin into the jaws the spring bias load must be overcome as the jaws are moved axially rearwardly and radially outwardly. In some assembly operations such insertion loads can be undesirably high.
A solution to this was to provide a structure in which the jaws, which are conventionally constructed to hardened steel, are secured to an elastomeric structure such that the jaws are generally axially fixed relative to each other and axial misalignment is substantially precluded. This is shown in the U.S. Pat. No. 4,347,728 issued on Sept. 7, 1982 to Smith. While that structure resulted in a significant improvement, when one of the jaws eventually failed or became detached from the elastomeric structure, the entire jaw assembly had to be replaced. The present invention is an improvement on that structure and while providing the advantage of that structure also permits replacement and facilitates assembly of individual jaw members. Thus it is an object of the present invention to provide an improved jaw structure of the type shown in the noted Smith patent in which the jaw segments can be readily assembled and replaced.
It is another general object to provide a new and improved jaw structure for tools for setting fasteners of the type having a pin with pull grooves .